Surveyor&#39;s instrument.



C. L. BERGER.

SURVEYORS INSTRUMENT.

APPLICATION FILED MAY 7. 1913.

Patented Apr. 13, 1915.

THE NORRIS PETERS 60.. PHOTU-LITHQ. WASHINGTON. D. C

CHRISTIAN L. BERGER, OF BOSTON, MASSACHUSETTS.

SUBVEYORS INSTRUMENT.

Specification of Letters Patent.

Patented Apr. 13, 1915..

Original application filed March 4, 1912, Serial No. 681,547. Divided and this application filed May 7, 1913.

Serial No.

To all whom it may concern Be it known that I, CHRISTIAN L. BERGER, a citizen of the United States, and resident of Boston, county of Suffolk, and State of Massachusetts, have invented an Improve ment in Surveyors Instruments, of which the following description, in connection with the accompanying drawings, is a specification, like letters on the drawings representing like parts.

This invention relates to surveyors instruments, and particularly to that type known as transits or Y levels, and is a divisional application of my pending application for patent Serial No. 681,517.

It is a particular object of my present invention to improve and perfect the well known type of Y levels used in surveying, but particularly to improve and perfect the construction of the mounting, carrying, and adjusting devices for the telescope of such levels. The present application, therefore, while primarily intended to be employed in a Y level, is of course capable of utilization in any instrument of precision employing a telescope or like instrument, whether or not it is intended for use as a transit.

In instruments of the kind described, where great precision is desirable it is, of course, necessary that adjusting devices be provided which will be capable of greatest accuracy of movement and which will stay in adjusted position. Also that provision be made enabling the various parts of the instrument to respond easily, readily, accurately and without binding, to all such adjustments which may be made.

To this end it is a special object of the present invention to provide an improved construction, wherein the telescope supporting means shall be capable of a wide range of adjustment, will be readily locked or held in adjusted position, and will permit responsive movement of the telescope without binding in any of its parts or bearings.

Other important features, details of construction, and combinations of parts will be hereinafter more fully pointed out and claimed.

Referring to the accompanying drawings, wherein a preferred embodiment of my 1nvention is shown as applied to a Y level, Figure 1 is a side elevation of the telescope, the cross-bar and leveling head; Fig. 2 1s a v ew partly in cross-section on the line 2-2 of Fig. 1; Fig. 3 is an end view of the front Y; Fig. 4 is a view, partly in cross section, on the line H of Fig. 1; and Fig. 5 is a view on the line 55 of Fig. 1.

Any suitable or usual type of telescope 1 may be employed, which is supported by front and rear Y arms which are formed on opposlte end portions of a cross-bar 2. This cross-bar is of novel construction, and has its forward portion in two horizontal sections, the lower section being indicated at 3. The telescope is preferably provided with collars 4 and 5 affixed upon the barrel at appropriate positions to rest in the forward and rear Y supports. These collars have flanges 6 and '2' respectively, each flange being formed on its collar and arranged to contact with the outside of its respective adacent Y support and thus act to prevent longitudinal movement of the telescope. These collars are each of similar diameter and their outer bearing surfaces are carefully arranged to be concentric with the line of collimation of the telescope. The forward Y support has a clamp 8 pivoted at 9 to one upstanding arm, and the free end of the clamp 8 is arranged to fit into a socket 10 in the other arm, and is provided with a notch or hole so that a pin 11 may be used to fit therein and thus lock the clamp 8 when in lowered position. Bearings 12 are preferably arranged in the lower part of the forward Y support as indicated in Fig. 3, these bearings being of any suitable metal and either fitted into sockets bored therefor in the Y support or otherwise secured. Threaded through the center of the top of the clamp 8 is a thrust screw 13 which may be adjusted to bear properly on the top of the collar 4 and thus hold the collar firmly upon the two lower bearings 12. A horizontal pin 14: is also secured to the clamp 8 and is adapted to engage with a notch in the flange 6 so that, when the clamp 8 is swung into its downward position to hold the telescope in the supporting Ys, the engagement of the pin 11 with the notch will prevent any rotative movement of the telescope.

The rear Y 15 has a clamp 16 pivoted at 17 to one arm of the Y and fitting in a socket cut therefor in the other arm of the Y in a similar manner to that just described in connection with the front Y. Two bearing members 18 are threaded through tapped holes in the opposite arms of the rear Y, as shown in Fig.2, beingsimilar in their position to the fixed bearings 12 of the front Y. The bearing members 18, however, are preferably arranged to be adjusted from the outside of the Y arms, being slightly longer than the tapped holes through which they are threaded andhaving slotted heads which will receive a common screwdriver to rotate them and give them any desired adjustment, A vertical thrust screw 19 is also threaded through the top of the clamp 16 to bear upon the top of the col-lar 5 and hold it firmly upon the lower bearing members 18 when the clamp 16 is in its locked position. In order to hold the threaded bearings 18 in their respective adjusted positions, set screws may be threaded through the Y arms at right angles to the tapped holes containing said members, one such set screw being indicated at 20 in Fig. 1. V

The cro'ss bar 2 is of novel form, being preferably convex on its outer sides with a tumble home so as to present substantially a semi-circular form in cross section. The forward portionof the cross-bar 2 is sawed horizontally for a considerable length, the lower portion 3 being of considerably greater size and strength than the upper portion. Threaded through the forward portion 3' is a capstan screw 21, which screw 7 is arranged to bear against the upper portion of the cross-bar. This construction permits a fine vertical adjustment of the forward Y support, as proper rotation of the capstan screw 21 will force the upper portion of the cross-bar carrying the front Y upwardly relatively with the lower portion 3 and the restof the cross-bar.- The portion 3' comprising the continuous convex sides and bottom of the cross-bar aflords' sufficient. rigidity to spring the upper part slightly to effect this adjustment; Preferably a tightening screw 22 is provided which may beconveniently positioned through the bearing s'crew 21iand has a collar or shoulder 22 contacting on the head of thescrew 21 and with its inner end threaded into a suitably tapped hole 23 in the upper portion of the cross-bar. When the screw21 is manipulated to make a desired adjustment, the tightening screw 22 may be rotated to lock the two portions in their ad:- ju'ste'd relation, as will be readily understood on reference-to Fig. 3. If desired, the bearing screw 21 mayhave its bearing end slightly concave and the corresponding portion against which it abuts may be formed as a boss; 24 or any suitable bearing block may be utilized. I

Fixed to the central portion of. the crossbar '2 is the supporting post or stem- 25 which is held in a suitable socket formed in a leveling head 26, the lower portion of the post 25 being beveled and preferably resting against a corresponding bearing surface, as set forth in my copending application above mentioned. The leveling head 26 is provided \iith a plurality of leveling screws 27 having a ball and socket engageinent with the caps 28 and resting on the top surface of the foot-plate 29 in a usual and well known manner. The upper ends of these leveling screws 27 are preferably extended through the leveling head 26 and are covered by caps to protect the leveling screws in their sockets in a novel manner. A tangent bracket 31 is afiixed to the cross bar and a spirit level 32 afiixed to the telescope 1 is shown in the conventional form.

The cross bar 2 is formed in a rounded or partially circular shape in cross section, having the upper portions of its sides 33 and 34 (see Figs. 2 and 5) between the Y supports inclined inwardly or with a pronounced tumble home. This construction, besides adding strength to the entire cross bar structure, acts very materially to protect the spirit level 32 in the greatest degree practical, while not interfering with the operators view thereof, and also said level and the interior of the cross bar 2 are in turn protected from rain, dust, etc., by the overhanging sides of the telescope 1. A still further advantage of this rounded form of the cross bar 2 and the pronounced tumble home. of the upper sides is that a leather or other cover or finishing layer may be more easily applied and more permanently secured thereto, without presenting any exposed angles on which such leather or other cover may catch, and be displaced. The formation of the forward end of the cross bar 2. also provides means to. effect a much finer adjustment of the telescope 1 than has heretofore been possible, such adjustment furthermore being firmly, quickly and permanently locked when the same has been effected by the bearing bolt 21 and locking screw 22.. The rounded bearing of the boss 24: allows for such adjustment without any binding effect. The arrangement of the Y supports with a three-point bearing composed of the lower member 12 in the forward support (or 18 in the rear Y,) together with the respective thrust screws 13. and 19 also enable av similar suspension for the telescope. v Preferably the points of the members 12 and 18 which are adapted to bear upon the collars 4 and 5 of the telescope 1, are substantially true or slightly convex in their surfaces, so that, as the collars 4 and 5 are perfect cylinders, a single point of suspension is obtained at the bearing contact between the collars and these three-point supporting devices.

It will thus be seen that my present invention provides an improved construction,

whereby great facility for adjustment, with a high degree of delicacy and accuracy, is provided. Also that when the adjustments desired are made between the cross bar and the supporting telescope that it may be securely locked in adjusted position, so as to permanently secure the relationship between the cross bar and telescope. The curved form of the cross bar 2 with the top portions 3% and 35 tumbling home as shown, is of particular importance, providing a maximum of strength and securing great rigidity in the lower or half round part of the cross bar with a minimum of metal and weight, as well as protecting the level 32 and obtaining the benefit of being in turn protected by the overhanging sides of the telescope 1, and I consider this feature of particular importance, especially in an instrument of precision of the type herein disclosed.

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In a surveyors instrument, a cross-bar to hold a telescope, said cross-bar having one end portion formed in two parts, the upper part carrying supporting means for the telescope, and the lower part being of greater rigidity than said upper part, and means to move the upper art relatively with said lower part to efl dct an adjustment of the telescope support.

2. In a snrveyors instrument, a cross-bar having a Y-support arranged near its end to hold a telescope, one end portion of said cross-bar being formed in two horizontal sections, the upper section carrying a Y-support and the lower section being of relatively greater rigidity than the upper section, and tightening and bearing screws arranged through said lower parts to effect a relative adjustment of the upper part and the Y-support thereon.

In testimony whereof, I have signed my name to this specification, in the presence of two subscribing witnesses.

CHRISTIAN L. BERGER.

Witnesses:

DANIEL W. VVEIs, HARRY M. GRIFFIN.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. 0. 

